The finest Proof Brown examples graded by PCGS are 2 PR-66BN's. The finest Proof Red-Brown example graded by PCGS is
a single PR-66RB.
Sources and/or recommended
reading:"The PCGS Population Report, October 2003" by The
Professional Coin Grading Service

"Attribution Guide For United States Large Cents 1840-1857", 2nd
edition by J.R. Grellman and Jules Reiver